The research proposal focuses on three related areas. In the first component we outline a series of studies on pituitary hormones and tumours. Pituitary and circulating forms of prolactin in humans and rats will be examined. Using a newly developed bioassay for prolactin we propose to determine the relationship between prolactin levels determined by bioassay and radioimmunoassay in normal subjects and in patients or rats with pituitary tumours. A new estrogen and ovarian dependent pituitary protein has been identified in estrogen induced pituitary tumours in rats. The secretion of this new protein will be examined and analogous proteins will be sought in human pituitary tumours. A novel chondrocyte growth factor in the human pituitary will be purified and its biological effects characterized. Hypertension caused by a pituitary tumor will be studied. The second component of the research looks at the factors which regulate the secretion of placental hormones. Compelling evidence for several extra placental endocrine factors controlling p]lacental hormone secretion has been obtained. The precise nature and mechanisms by which rat placental lactogen synthesis and secretion is controlled will be examined in order to understand the mechanisms influencing human placental lactogen secretion in women. The third component of the research focuses on receptors for prolactin and growth hormone. Monoclonal antibodies, bifunctional cross linking agents and the Nb2 lymphoma cells will be used. Evidence for a peptide mediator (second messenger) of the action of prolactin has been obtained. Atempts will be made to purify and characterize this mediator. A possible role for prolactin and growth hormone in human lymphomas will be sought.